netfilter: conntrack: avoid reload of ct->status

Compiler can't merge the two test_bit() calls, so load ct->status
once and use non-atomic accesses.

This is fine because IPS_EXPECTED or NAT_CLASH are either set at ct
creation time or not at all, but compiler can't know that.

Signed-off-by: Florian Westphal <fw@strlen.de>

net/netfilter/nf_conntrack_core.c

@@ -1854,14 +1854,15 @@ resolve_normal_ct(struct nf_conn *tmpl,
 	if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 		ctinfo = IP_CT_ESTABLISHED_REPLY;
 	} else {
+		unsigned long status = READ_ONCE(ct->status);
+
 		/* Once we've had two way comms, always ESTABLISHED. */
-		if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
+		if (likely(status & IPS_SEEN_REPLY))
 			ctinfo = IP_CT_ESTABLISHED;
-		} else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
+		else if (status & IPS_EXPECTED)
 			ctinfo = IP_CT_RELATED;
-		} else {
+		else
 			ctinfo = IP_CT_NEW;
-		}
 	}
 	nf_ct_set(skb, ct, ctinfo);
 	return 0;

net/netfilter/nf_conntrack_proto_udp.c

@@ -88,6 +88,7 @@ int nf_conntrack_udp_packet(struct nf_conn *ct,
 			    const struct nf_hook_state *state)
 {
 	unsigned int *timeouts;
+	unsigned long status;
 
 	if (udp_error(skb, dataoff, state))
 		return -NF_ACCEPT;
@@ -96,26 +97,27 @@ int nf_conntrack_udp_packet(struct nf_conn *ct,
 	if (!timeouts)
 		timeouts = udp_get_timeouts(nf_ct_net(ct));
 
-	if (!nf_ct_is_confirmed(ct))
+	status = READ_ONCE(ct->status);
+	if ((status & IPS_CONFIRMED) == 0)
 		ct->proto.udp.stream_ts = 2 * HZ + jiffies;
 
 	/* If we've seen traffic both ways, this is some kind of UDP
 	 * stream. Set Assured.
 	 */
-	if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
+	if (status & IPS_SEEN_REPLY_BIT) {
 		unsigned long extra = timeouts[UDP_CT_UNREPLIED];
 		bool stream = false;
 
 		/* Still active after two seconds? Extend timeout. */
 		if (time_after(jiffies, ct->proto.udp.stream_ts)) {
 			extra = timeouts[UDP_CT_REPLIED];
-			stream = true;
+			stream = (status & IPS_ASSURED) == 0;
 		}
 
 		nf_ct_refresh_acct(ct, ctinfo, skb, extra);
 
 		/* never set ASSURED for IPS_NAT_CLASH, they time out soon */
-		if (unlikely((ct->status & IPS_NAT_CLASH)))
+		if (unlikely((status & IPS_NAT_CLASH)))
 			return NF_ACCEPT;
 
 		/* Also, more likely to be important, and not a probe */